This invention relates generally to a seating unit comprising side supports and a seat subassembly mounted thereon and is more particularly concerned with a concealed mounting for structurally integrating the seat subassembly into the seating unit.
Prior art seating units take many forms. One type of prior art seating unit generally comprises a main support structure which includes a pair of spaced opposed side support members connected together by transverse cross means. A seat subassembly is secured between the side support members. The need in such units is to provide a seating unit which will, when finally assembled, have an integrated strong structural inner frame capable of withstanding the multidirectional stresses imposed by people sitting in such units. Such units are placed in a heavy use environment, such as hospitals, psychiatric units, dormitories, hotels and other commercial establishments where the units are subject to heavy use and even abuse. If the seating unit can be made of all steel construction it is a relatively simple matter to design a seating unit that will withstand such stress and abuse.
However, the owners and operators of such establishments desire the beauty and warmth of natural hard woods, but it is difficult to design wood units that will stand such use. Thus, to provide the needed strength it has been the practice to make the highly visable main side supports out of beautiful hardwood and to provide a rigid steel frame for the upholstered back cushion and the horizontal seat cushion subassembly. The art of making concealed joints for exposed hard wood is well known and it is also well known that such joints provide points of weakness where the seating unit is likely to break when subjected to unusually high stresses imposed at unusual angles.
U.S. Pat. No. 4,488,755 issued December 18, 1984 to Leonard M. Nemschoff discloses one way of successfully integrating a steel inner frame with natural hardwood side supports in a manner that provides the seat unit with a strong structural integrity capable of withstanding all but the most unreasonably high stresses. This prior art design provides an inner frame which has some exposed metal portions. While such designs have been highly successful and well accepted by the market place because of their strength and durability, there is a class of customers, such as psychiatric hospitals that find that any exposed metal frame parts present risks and potential for the mentally disturbed to injure themselves. Thus, exposed metal parts may be unacceptable for some applications. Such customers and users demand seating units that combine the beauty of natural hard wood with an inner steel frame that is totally concealed to protect the person seated therein while also providing strength and durability. In other words such customers want a low cost chair with a custom built appearance that has industrial strength and durability. However, these customers, and particularly institutional purchasing departments, do not desire to pay the high costs that have heretofore been associated with the manufacture and assembly of such seating units.
From the foregoing it will be appreciated that there are several existing problems. Foremost is the problem of providing structural integrity between the wood frame and a seat subassembly having an inner steel frame. In addition there is the problem of how to conceal all mounting means to minimize potential for injury. Further there is the problem of how to provide a concealed mounting means that is a paragon of simplicity in order to lower manufacturin costs to a minimum while providing a rugged seating unit wherein the inner steel frame of the seat subassembly is connected in a concealed manner to reinforce the hard wood side supports and provide structural integrity to the assembled seating unit. Still further there is the problem of accomplishing the above by providing an inner steel frame seat subassembly that can be mounted on the main frame in virtually a few minutes to significantly reduce assembly costs.
A related problem is to provide a simple concealed mounting for the internal steel frame that will permit the manufacturer to quickly upholster the seat subassembly and which will permit the end user to quickly remove the upholstered seat subassembly from the side supports for reupholstering in a short time with a premanufactured original factory quality upholstery cover without the need to send the entire seat unit to an upholstery shop. Not only does this reduce upholstery costs but it avoids the need to take the seating unit out of service for days or weeks.